Global vulnerability to near-Earth object impact

A clear appreciation of the consequences resulting from an asteroid impact is required in order to understand the near Earth object (NEO) hazard. Three main processes require modelling to analyse the entire impact event. These are the atmospheric entry phase, land impact events and ocean impact events. A range of impact generated effects (IGEs) are produced by different impact scenarios. It is these IGEs that present the threat to human populations world wide, and the infrastructure they utilise. A software system for analysing the NEO threat has been developed, entitled NEOimpactor, to examine the social and economic consequences from land and ocean impacts. Existing mathematical models for the three principal impact processes have been integrated into one complete system, which has the capability to model the various effects of a terrestrial asteroid impact and, critically, predict the consequences for the global population and infrastructure. Analysis of multiple impact simulations provides a robust method for the provision of an integrated, global vulnerability assessment of the NEO hazard. The primary graphical outputs from NEOimpactor are in the form of ‘relative consequence’ maps, and these have been designed to be comprehensible to a non-specialist audience. By the use of a series of multiple-impact simulations, the system has identified the five countries most at risk from the impact hazard, as well as indicating the various factors influencing vulnerability

Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

Several specimens of Libyan Desert Glass (LDG), an enigmatic natural glass from Egypt, were subjected to investigation by micro-Raman spectroscopy. The spectra of inclusions inside the LDG samples were successfully measured through the layers of glass and the mineral species were identified on this basis. The presence of cristobalite as typical for high-temperature melt products was confirmed, together with co-existing quartz. TiO2 was determined in two polymorphic species, rutile and anatase. Micro-Raman spectroscopy proved also the presence of minerals unusual for high-temperature glasses such as anhydrite and aragonite

Impact Craters and Meteorites: The Egyptian Record

This chapter provides an account of the present Egyptian impact cratering record as well as an overview of the Egyptian meteorite collection. The 45-m-diameter Kamil crater in the East Uweinat District in southwestern Egypt is so far the only confirmed impact crater in Egypt. Due to its exceptional state of preservation Kamil can be considered a typestructure for small-scale impacts on Earth. Enigmatic types of natural glasses including the Libyan Desert glass found in the Great Sand Sea and the Dakhleh glass found near Dakhla Oasis (note that Dakhla, Dakhleh and Dakhla are synonyms) may be products of low-altitude airbursts of large and fragile cometary or asteroidal impactors. A number of circular, cratershaped geological structures superficially resembling impact craters are discussed. To date the Egyptian meteorite collection totals 2 falls, including the ~10 kg Martian meteorite Nakhla that has served as a keystone for the understanding of magmatic differentiation processes on Mars, and 76 finds. With the exception of a minority of incidental findings, most Egyptian meteorite finds (~75%) were recovered over the last ~30 years from three dense meteorite collection areas, namely the El-Shaik Fedl, Great Sand Sea and Marsa Alam fields. The exceptional exposures of the Precambrian basement and Paleozoic to Cenozoic sedimentary covers in Egypt offer a good opportunity for the identification of new impact structures. Likewise, Egypt’s vast rocky desert surfaces are of great potential for the collection of meteorites through systematic searches. These prospects are fundamental ingredients for fostering the ongoing development of meteoritics and planetary science in Egypt as disciplines for future scientific endeavor in Africa